Brittany Packnett was sitting anxiously in the Oval Office last month when she decided to disregard friends' advice and tell Barack Obama about her first taste of tear gas. It came on a street in Ferguson, Mo., as she stood next to a petrified eighth-grader.

"I was afraid of sounding like an angry black woman at the White House,'' says Packnett, one of several young civil rights activists in the meeting. "But I needed the president to know what middle-schoolers faced in their neighborhood.''

So she spoke up — sustained, she says, on this and other recent occasions by words of Martin Luther King Jr.: "Injustice anywhere is a threat to justice everywhere.''